Expanded fluids used in a heat exchanger



OC- 19, 1965 E. A. HARPER ETAL 3,212,277

EXPANDED FLUIDS USED IN A HEAT EXCHANGER Filed June 20, 1962 A 7' TORNE KS` United States Patent O 3,212,277 EXPANDED FLUIDS USED IN A HEAT EXCHANGER Ernest A. Harper, Joseph T. Karbosky, and Frederic N.

Hull, Bartlesville, Okla., assignors to Phillips Petroleum Company, a corporation of Delaware Filed June 20, 1962, Ser. No. 203,859 7 Claims. (Cl. 62-23) This invention relates to method and apparatus for providing a substantially uniform distribution of a fluid which has two phases. In one aspect the invention relates to method and apparatus for feeding a uniform concentration of both liquid and vapor through a plurality of flow paths. In another aspect the invention relates to method and apparatus for feeding a substantially uniform concentration of liquid and vapor through a multiple passage heat exchanger. In a still further aspect the invention relates to method and apparatus for flashing a liquid, recovering the flashed liquid and the flashed vapors, and passing a substantially uniform concentration of the flashed liquid and flashed vapors through a plurality of flow paths.

In the separation of helium from natural gas by low temperature refrigeration, it is desirable in some instances to reduce the pressure on the liquefied gases that are separated from the helium, before the separated liquids are passed through a heat exchanger in order to have the liquefied gases at a pressure at which substantially all of the liqueed gases will be vaporized by passage through the heat exchanger. When the pressure is reduced, flashing occurs, and it is difficult to pass a uniform concentration of the resulting two phase fluid through the various passes of the heat exchanger. If most of the flashed liquid is allowed to pass through some of the passes and the flashed vapor is allowed to pass through the other passes, the amount of liquid vaporized will be decreased, resulting in less heat being transferred as well as an unequal distribution of the heat. For a maximum transfer of heat, it is desirable for a uniform concentration of the various constituents of the fluid to pass through each of the passes in the heat exchanger.

In accordance with the invention it has been discovered that these difficulties can be overcome, if not eliminated entirely, by separating the flashed liquid and the flashed vapor, introducing a substantially equal portion of the flashed liquid into each of the plurality of flow` paths through the heat exchanger, and introducing substantially equal portions of the flashed vapors into each of the plurality of flow paths.

In a presently preferred embodiment of the invention, there is provided a heat exchanger having a first and second plurality of flow passageways therethrough, a header connected to said heat exchanger to form a chamber in fluid communication with one end of each of the first plurality of flow passageways, a first conduit means for introducing the flashed vapor into said chamber, a second conduit means positioned within said chamber and having a plurality of openings disposed radially of said second conduit means adjacent each of said one end of said first plurality of flow passageways and directed toward the ICC respective said each of said one end, and means for n-` troducing the flashed liquid into said second conduit means.

Accordingly it is an object of the invention to provide method and means for obtaining a substantially uniform distribution of a fluid having two phases through a plurality of flow paths. Another object of the invention is to provide a uniform distribution of heat in a heat exchanger. Another object of the invention is to provide for maximum transfer of heat in a heat exchanger. A still further object of the invention is to provide substantially uniform concentration of both liquid and vapor through a plurality of flow paths in a heat exchanger.

Other objects, aspects and advantages of the invention Will be apparent from a study of the disclosure, the drawings and the appended claims to the invention.

In the drawings FIGURE l is a diagrammatic representation of a low temperature refrigeration separation process embodying the invention; FIGURE 2 is an elevation view in cross section of a presently preferred apparatus; and FIGURE 3 is a cross sectional view of the apparatus of FIGURE 2 taken along the line 3 3.

Referring now to the drawings in detail, and to FIG- URE l in particular, natural gas containing hydrocarbons, nitrogen, and helium is passed through line 11 into and through flow paths 12 and 13 of heat exchanger 14 wherein the gas is substantially cooled. The thus cooled gas is passed through line 15 into liquid-gas separator 16. The flow of gas through line 11 can be maintained substantially constant by means of valve 17 which is located in line 11 and is controlled by flow rate controller 18 responsive to the differential pressure across an orifice 19 located in line 11.

The vapors from liquid-gas separator 16 are withdrawn through line 21 and passed to separation zone 22 wherein a further separation is made. Separation zone 22 can be any suitable means, such as, for example, a series of heat exchangers and liquid-gas separators. A crude helium stream obtained in separation zone 22 is passed through line 23 and flow path 24 of heat exchanger 14, and is Withdrawn from the system by way of line 25. A low B.t.u. gas obtained in separation zone 22 is passed through line 26 and flow path 27 of heat exchanger 14 and is withdrawn from the system by way of line 28. A residue gas obtained in separation zone 22 is passed through line 29 and flow path 31 of heat exchanger 14 and is withdrawn from the system by way of line 32.

The liquid in liquid-gas separator 16 is withdrawn therefrom by way of line 33. The rate of flow through line 33 can be controlled to maintain the liquid level in separator 16 substantially constant by means of a throttling valve 34 which is actuated by liquid level controller 35. Throttling valve 34 also functions to decrease the pressure of the fluid passing therethrough, whereby flashing occurs. The fluid leaving valve 34 is passed by way of line 36 into liquid-gas separator 37. The flashed vapors are withdrawn from separator 37 by way of line 38 and are passed through flow paths 39, 41, 42 and 43 of heat exchanger 14. The rate of flow through line 38 can be controlled by means of valve 44 which is actuated by liquid level controller 45 responsive to the liquid level in separator 37, as a means of maintaining the pressure 3 of the flashed vapors downstream of valve 44 slightly lower than the pressure of the flashed liquid. The lashed liquid is withdrawn from separator 37 by way of line 46 and is introduced into ilow paths 39, 41, 42 and 43 in 4 While heat exchanger 14 has been illustrated with flow paths 12a, 12b, 13a, 13e, 24, 27, 31, 39, 41, 42 and 43, it is obvious that any desired number of ow paths can be utilized for each of the streams passing through heat such a manner that the concentrations of liquid and 5 exchanger 14. Also, while the invention has been illusvapor passing through each of ilow paths 39, 41, 42 and trated in connection with a refrigeration separation lsystem 43 are substantially the same. Substantially all of the for the recovery of helium the invention can be utilized at liquid passing through flow paths 39, 41, 42 and 43 iS any time when it is desired to pass a substantially uniform vaporized by the transfer of heat thereto from the feed concentration of a two phase iluid through a plurality of stream passing through flow paths 12 and 13. The vapor- 10 flow paths. ized etiluent of ow paths 39, 41, 42 and 43 is combined The following examples are presented 1n further illusand withdrawn from the system by way of line 47- tration of the invention and are not to be unduly con- Referring now to FIGURES 2 and 3 there is illustrated strued in limitation thereof. the presently preferred apparatus for recombinirig the flashed liquid and the flash vapors. For purposes of 15 EXAMPLE I simplicity only that portion of heat exchanger 14 involving ow paths 1213, 39, 41, 42 and 43 are shown. A heat exchanger having a first plurality of flow paths Heat exchanger 14 comprises a rst plurality of flow for the fluid to be cooled, a second plurality of .flow paths paths 12a, 12b, 13a, and 13b through which the feed for the cooling fluid, each ofthe secondplurality of flow stream to be cooled is passed; a second plurality of flow paths having a rectangular inlet approximately 4 inches' paths 39, 41, 42, and 43 through which the cooling Huid by 1A inch, a plenum chamber enclosing the inlets of said is passed; a rst plenum chamber 51 which is in lluid comsecond plurality of flow paths, a liquid header mounted munication between line 11 and the inlets of each of flow inside of said plenum chamber, said header having 6 openpaths 12a, 12b, 13a and 13b; a second plenum chamber ings radially disposed therein above each of said inlets of 52 which `is in fluid communication between vapor inlets 25 said second plurality of flow paths, the velocity of the 38a and 3817 and the inlets of each of ilow paths 39, 41, liquid jets from said openings being approximately 14' 42 and 43; and a liquid header 53 positioned within the feet/second, the velocity of vapors through said plenum second plenum chamber 52.` In order to provide for equal chamber being approximately 18 feet/ second, is utilized distribution of the liquid from line 46 to each of flow in the refrigeration separation system of FIGURE l with paths 39, 41, 42 and 43 as well as for equal distribution 30 the condition set forth in Table I.

Table I Composition, Mol Percent Component Tempera- Pressure, Flow,

ture, F. p.s.i.a. lbs/hr. He N2 Ci C2 C3 C4 C5 11 0. 75 14.84 00 850 250,813 15-- 0.75 14.84 -80 348 250, 813 10.. 0.75 14.84 -80 848 250,813 21.--- 0.84 10.54 -80 845 200,508 23-- 55.01 40.88 -90 7i 2, 305 25 55.01 40.83 81 00 2,305 20.- 0.08 57.08 -90 72 20,829 28.- 0.03 57.08 81 71 20,829 29-- 0.01 10.99 83.14 4.88 0.84 0.12 0. 01 -90 223 171,874 82 0. 01 10.89 83.14 4. 88 0.84 0.12 0. 01 81 222 171,374 83 1.40 20. 52 21. 24 80.37 14.07 0.40 80 848 50, 805 80.- 1. 20.52 21.24 80.37 14. 07 0.40 130.5 20 50,805 87 1.40 20.52 21.24 80.37 14. 07 0.40 *180.5 20 50, 805 88 4.35 79. 20 14.19 1.87 0.80 0.03 A w180.5 20 ,228 40 0.08 2.07 24.51 48. 00 20.44 9.85 180.5 20 42,077 47 1. 40 20.52 21. 24 80.87 14. 07 0.40 8i i8 50,305

across each of the flow paths, header 53 is provided with a plurality of openings 54 radially disposed therein above each of the ow paths 39, 41, 42, and 43 and directed towards the inlet of the respective flow path. For successful operation it is desirable that the liquid being introduced into each of ow paths 39, 41, 42 and 43 be divided into a plurality of high velocity streams in order to prevent or substantially eliminate blowing of the liquid away from the ow path inlet by the vapor ow. While the liquid can be introduced into the flow paths at any suitable rate, the presently preferred speed of the liquid streams into the flow paths is in the range of about 5 to about 16 feet per second. Similarly while the vapors can be introduced into the flow paths at any suitable rate, the presently preferred rate is in the range of about 5 to about 20`feet per second.

Referring now to FIGURE 3, each of the rectangular ow paths 39, 41, 42 and 43 can be provided with a fluid diffuser 55 which comprises a section 56 disposed below header 53 and having vertical passageways, sections 57 andk 58 disposed on each side of section 56 and having passageways inclined at a suitable angle to the vertical and communicating with the passageways of section 56, and a plurality of horizontal diffusion screens 59.

The resulting heat transfer rate between the mixture of flashed vapors from line 38 and ashed liquid from line 46 with the feed stream of line 11 is considerably better in comparison to a system wherein there is a maldistribution of the liquid and vapor of any consequence;

EXAMPLE Il A heat exchanger having a rst plurality of flow paths for the uid to be cooled, a second plurality of How paths for the cooling fluid,` each of the second plurality of flow paths having a rectangular inlet approximately 4 inches by A inch, a plenum chamber enclosing the inlets of said second plurality of flow paths, a liquid header mounted inside of said plenum chamber, said header having 8 openings radially disposed therein above each of said inlets -of said second plurality of flow paths, the velocity of the liquid jets from said openings being approximately 16 feet/second, the velocity of vapors through said plenum chamber being approximately 20 feet/ second', is utilized in a refrigeration separation system similar to that of FIGURE 1 except that the residue gas in line 29 is introduced into line 38 and therein admixed with the ashed vapors from separator 37, rather than passing through separate flow path 31, with the conditions set forth in Table 1I.

gas separator; means for passing the thus cooled and partially liquefied fluid stream into said first liquid-gas sep- Table II Composition, Mol Percent Component Tempera- Pressure, Flow,

ture, F. p.s.i.a. lbs/hr.

He N2 Ci C2 C3 C4 C5 0.84 16. 54 77. 43 4. 29 0. 77 0. 11 0. 02 -80 345 200, 508 0.84 16. 54 77. 43 4. 29 0. 77 0. ll 0. 02 -165 345 200, 508 0. 84 16. 54 77. 43 4. 29 0. 77 0. 11 0. 02 -165 345 200, 508 1. 44 24. 51 73. 77 0. 28 -165 343 116, 887 55. 01 40. 83 4. 16 -175 73 2, 305 55. 01 40. 83 4. 16 -90 71 2, 305 0. 03 57. 68 42. 29 -175 73 26, 829 0. 03 57. 68 42. 29 -90 72 26, 829 0. O1 16. 04 83. 60 0.35 -175 225 87, 753 0. 02 5. 46 82. 52 9. 87 1. 83 07 0. 03 -165 345 83, 621 0. 02 5. 46 82. 52 9. 87 1.83 0. 07 0. 03 -180 230 83, 621 0. 02 5. 46 82. 52 9. 87 1.83 07 0 03 -180 230 83, 621 0. 19 21. 98 77. 55 0. 28 -180 23() 7, 596 3. 81 83. 02 10. 82 2. 02 0. 30 0 03 -180 230 76, 025 0 0l 10. 99 83. 14 4. 88 0. 84 0. 12 0. 01 -90 223 171, 374

Again the heat exchanger embodying the present invention for utilization with two phase fluid ilow provides greater heat transfer than a system wherein there is a maldistribution of the liquid and vapor phases of any consequence.

Reasonable variation land modication are Ipossible within the scope of the disclosure, the drawings and the appended claims to the invention.

We claim:

1. Apparatus for utilizing a high pressure liquid stream as a cooling lluid in a heat exchanger having a plurality of flow paths therethrough and wherein it is desirable that substantially all of the cooling fluid be vaporized in passing through said heat exchanger although said liquid stream is at a pressure higher than the pressure at which substantially all of said liquid stream would be vaporized by being passed through said heat exchanger, and wherein said liquid stream would have a liquid phase and a gas phase upon the pressure of said liquid stream being reduced to said pressure at which substantially all of said liquid stream would be vaporized by being passed through said heat exchanger, comprising a heat exchanger having a rst plurality of flow paths therethrough for the passage of a uid to be cooled and a second plurality of rectangular ow paths therethrough for the passage of a cooling fluid, means for forming a chamber in lluid communication with one end of each rof said second plurality of flow paths, a distribution conduit positioned within said charnber and having a plurality of openings disposed radially in said conduit adjacent each of said one end of said second plurality of ilow paths, means for reducing the pressure on said liquid stream to said pressure at which substantially all of said liquid stream would be vaporized by being passed through said heat exchanger, a gas-liquid separator, irst conduit means for introducing the liquid stream at the reduced pressure into said separator, second conduit means connected to a lower portion `of said separator for passing liquid from said separator into said distribution conduit, and third conduit means connected to an upper portion of said separator for passing vapor from said separator into said chamber.

2. Apparatus for separating a fluid stream into at least two components comprising a heat exchanger having a first plurality of ow paths therethrough for the passage of a fluid to be cooled and a second plurality of flow paths therethrough for the passage of a cooling fluid, means for forming a chamber in fluid communication with one end of each of said second plurality of flow paths, a vapor inlet for introducing vapor into said chamber, a liquid distribution conduit positioned Within said chamber and having a plurality of openings disposed radially in said conduit adjacent each of said one end of said second plurality of flow paths; means for passing said fluid stream through said rst plurality of flow paths to substantially cool and partially liquefy said fluid stream; a first liquidarator; means for withdrawing a liquid stream from said irst liquid-gas separator, the pressure in said first liquidgas separator being higher than the pressure at which substantially all of said liquid stream would be vaporized by being passed directly through said second plurality of flow paths; means for reducing the pressure on said liquid stream to said pressure at which substantially all of said liquid stream would be vaporized by being passed through said second plurality of flow paths and thereby forming a liquid phase and a gas phase; a second liquid-gas separator; rst conduit means for introducing said liquid stream at the thus reduced pressure into said second liquid-gas separator; second conduit means connected to a lower portion of said second liquid-gas separator for passing liquid from said second liquid-gas separator into said distribution conduit, and third conduit means connected to an upper portion of said second liquid-gas separator for passing vapor from said second liquid gas separator through said vapor inlet into said chamber.

3. Apparatus in accordance with claim 2 further comprising means for determining the liquid level in said rst liquid-gas separator and controlling said means for reducing responsive thereto to maintain the said liquid level substantially constant.

4. Apparatus in accordance with claim 3 further comprising means for determining the liquid level in said second liquid-gas separator and for controlling the passage of vapor through said third conduit means responsive thereto to maintain the liquid level in said second liquidgas separator substantially constant.

5. Apparatus for utilizing a high pressure liquid stream as a cooling fluid in a heat exchanger having a plurality of flow paths therethrough and wherein it is desirable that substantially all of the cooling fluid be vaporized in passing through said heat exchanger although said liquid stream is at a pressure higher than the pressure at which substantially all of said liquid stream would be vaporized by being passed through said heat exchanger, and wherein said liquid stream would have a liquid phase and a gas phase upon the pressure of said liquid stream being reduced to said pressure at which substantially all of said liquid stream would be vaporized by being passed through said heat exchanger, comprising a heat exchanger having a plurality of flow paths therethrough for the passage of a cooling fluid, means for forming a chamber in fluid cornmunication with the inlet ends of each of said plurality of flow paths, a distribution conduit positioned within said chamber and having a plurality of openings disposed radially in said distribution conduit adjacent each of said inlet ends of said plurality of ilow paths and directed toward the respective one of said inlet ends for introducing substantially equal portions of liquid into each of said plurality of iiow paths, means for reducing the pressure on said liquid stream to said pressure at which substantially all of said liquid stream would be vaporized by being passed through said heat exchanger, a gas-liquid separator, rst conduit means for introducing the liquid stream at the reduced pressure into said separator, second conduit means connected to a lower portion of said separator for passing liquid from said separator into said distribution conduit, third conduit means connected to an upper portion of Said separator for passing vapor from said separator into said chamber to introduce substantially equal portions of the vapor into each of said plurality of flow paths, valve means operatively connected in said third conduit means, a liquid level indicator operatively connected to said separator and adapted to produce a signal representative of the liquid level in said separator, and means for actuating said valve responsive to said signal.

6. Apparatus in accordance with claim wherein said distribution conduit has at least six openings disposed radially therein adjacent each of said inlet ends.

7. Apparatus comprising a heat exchanger having a rst plurality 0f ow paths therethrough for the passage of a uid to be cooled and a second plurality of flow paths therethrough for the passage of a cooling fluid, means for forming a chamber in fluid communication With one end of each of said second plurality of flow paths, a distribution conduit positioned within said chamber and having at least one opening disposed radially in saidk conduit adja-l References Cited by the Examiner UNITED STATES PATENTS 2,022,165 ll/ Twomey 62-23v X 2,229,940 1/4l Spofford 62-525 2,592,712 4/52 Knoy 62-491- X 2,849,867 9/58 Haringhuizen.

2,900,312 8/59 Gilmore 202-160 2,939,293v 6/ 60 Green 62-21 3 ,018,229 1/ 62 Morgan.

3,026,682 3/62 Palazzo 62-23 X NORMAN YUDKOFF, Primary Examiner. 

1. APPARATUS FOR UTILIZING A HIGH PRESSURE LIQUID STREAM AS A COOLING FLUID IN A HEAT EXCHANGER HAVING A PLURALITY OF FLOW PATHS THERETHROUGH AND WHEREIN IT IS DESIRABLE THAT SUBSTANTIALLY ALL OF THE COOLING FLUID BE VAPORIZED IN PASSING THROUGH SAID HEAT EXCHANGER ALTHOUGH SAID LIQUID STREAM IS AT A PRESSURE HIGHER THAN THE PRESSURE AT WHICH SUBSTANTIALLY ALL OF SAID LIQUID STREAM WOULD BE VAPORIZED BY BEING PASSED THROUGH SAID HEAT EXCHANGER, AND WHEREIN SAID LIQUID STREAM WOULD HAVE A LIQUID PHASE AND A GAS PHASE UPON THE PRESSURE OF SAID LIQUID STREAM BEING REDUCED TO SAID PRESSURE AT WHICH SUBSTANTIALLY ALL OF SAID LIQUID STREAM WOULD BE VAPORIZED BY BEING PASSED THROUGH SAID HEAT EXCHANGER, COMPRISING A HEAT EXCHANGER HAVING A FIRST PLURALITY OF FLOW PATHS THERETHROUGH FOR THE PASSAGE OF A FLUID TO BE COOLED AND A SECOND PLURALITY OF RECTANGULAR FLOW PATHS THERETHROUGH FOR THE PASSAGE OF A COOLING FLUID, MEANS FOR FORMING A CHAMBER IN FLUID COMMUNICATION WITH ONE END OF EACH OF SAID SECOND PLURALITY OF FLOW PATHS, A DISTRIBUTION CONDUIT POSITIONED WITHIN SAID CHAMBER AND HAVING A PLURALITY OF OPENINGS DISPOSED RADIALLY IN SAID CONDUIT ADJACENT EACH OF SAID ONE END OF SAID SECOND PLURALITY OF FLOW PATHS, MEANS FOR REDUCING THE PRESSURE ON SAID LIQUID STREAM TO SAID PRESSURE AT WHICH SUBSTANTIALLY ALL OF SAID LIQUID STREAM WOULD BE VAPORIZED BY BEING PASSED THROUGH SAID HEAT EXCHANGER, A GAS-LIQUID SEPARATOR, FIRST CONDUIT MEANS FOR INTRODUCING THE LIQUID STREAM AT THE REDUCED PRESSURE INTO SAID SEPARATOR, SECOND CONDUIT MEANS CONNECTED TO A LOWER PORTION OF SAID SEPARATOR FOR PASSING LIQUID FROM SAID SEPARATOR INTO SAID DISTRIBUTION CONDUIT, AND THIRD CONDUIT MEANS CONNECTED TO AN UPPER PORTION OF SAID SEPARATOR FOR PASSING VAPOR FROM SAID SEPARATOR INTO SAID CHAMBER. 